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Commit 9e9a95b3 authored by Phil Burk's avatar Phil Burk
Browse files

aaudio: fix race condition in requestStart() 

Set callback enable flag before starting AudioTrack callback.

Bug: 72115512
Test: Repeat:  adb shell write_sine_callback -pn -s4
Test: 20 times and make sure framesWritten is advancing.
Change-Id: I670fde46da0dccf8a6d03478fe2aa8b7ad596a3b
parent 87b46795

media/libaaudio/src/legacy/AudioStreamLegacy.cpp

+7 −2
Original line number Diff line number Diff line
@@ -86,10 +86,15 @@ void AudioStreamLegacy::processCallbackCommon(aaudio_callback_operation_t opcode 
            // AudioRecord::Buffer

            // TODO define our own AudioBuffer and pass it from the subclasses.

            AudioTrack::Buffer *audioBuffer = static_cast<AudioTrack::Buffer *>(info);

            if (getState() == AAUDIO_STREAM_STATE_DISCONNECTED || !mCallbackEnabled.load()) {

            if (getState() == AAUDIO_STREAM_STATE_DISCONNECTED) {

                ALOGW("processCallbackCommon() data, stream disconnected");

                audioBuffer->size = SIZE_STOP_CALLBACKS;

            } else if (!mCallbackEnabled.load()) {

                ALOGW("processCallbackCommon() stopping because callback disabled");

                audioBuffer->size = SIZE_STOP_CALLBACKS;

            } else {

                if (audioBuffer->frameCount == 0) {

                    ALOGW("processCallbackCommon() data, frameCount is zero");

                    return;

                }
@@ -106,7 +111,7 @@ void AudioStreamLegacy::processCallbackCommon(aaudio_callback_operation_t opcode 
                if (callbackResult == AAUDIO_CALLBACK_RESULT_CONTINUE) {

                    audioBuffer->size = audioBuffer->frameCount * getBytesPerFrame();

                } else { // STOP or invalid result

                    ALOGW("%s() stop stream by faking an error", __func__);

                    ALOGW("%s() callback requested stop, fake an error", __func__);

                    audioBuffer->size = SIZE_STOP_CALLBACKS;

                    // Disable the callback just in case AudioFlinger keeps trying to call us.

                    mCallbackEnabled.store(false);

media/libaaudio/src/legacy/AudioStreamLegacy.h

+0 −3
Original line number Diff line number Diff line
@@ -121,9 +121,6 @@ protected: 


    void forceDisconnect(bool errorCallbackEnabled = true);



    void onStart() { mCallbackEnabled.store(true); }

    void onStop() { mCallbackEnabled.store(false); }



    int64_t incrementFramesWritten(int32_t frames) {

        return mFramesWritten.increment(frames);

    }

media/libaaudio/src/legacy/AudioStreamRecord.cpp

+4 −2
Original line number Diff line number Diff line
@@ -234,11 +234,13 @@ aaudio_result_t AudioStreamRecord::requestStart() 
        return AAudioConvert_androidToAAudioResult(err);

    }



    // Enable callback before starting AudioTrack to avoid shutting

    // down because of a race condition.

    mCallbackEnabled.store(true);

    err = mAudioRecord->start();

    if (err != OK) {

        return AAudioConvert_androidToAAudioResult(err);

    } else {

        onStart();

        setState(AAUDIO_STREAM_STATE_STARTING);

    }

    return AAUDIO_OK;
@@ -248,11 +250,11 @@ aaudio_result_t AudioStreamRecord::requestStop() { 
    if (mAudioRecord.get() == nullptr) {

        return AAUDIO_ERROR_INVALID_STATE;

    }

    onStop();

    setState(AAUDIO_STREAM_STATE_STOPPING);

    incrementFramesWritten(getFramesRead() - getFramesWritten()); // TODO review

    mTimestampPosition.set(getFramesRead());

    mAudioRecord->stop();

    mCallbackEnabled.store(false);

    mFramesRead.reset32();

    mTimestampPosition.reset32();

    // Pass false to prevent errorCallback from being called after disconnect

media/libaaudio/src/legacy/AudioStreamTrack.cpp

+5 −3
Original line number Diff line number Diff line
@@ -259,11 +259,13 @@ aaudio_result_t AudioStreamTrack::requestStart() { 
        return AAudioConvert_androidToAAudioResult(err);

    }



    // Enable callback before starting AudioTrack to avoid shutting

    // down because of a race condition.

    mCallbackEnabled.store(true);

    err = mAudioTrack->start();

    if (err != OK) {

        return AAudioConvert_androidToAAudioResult(err);

    } else {

        onStart();

        setState(AAUDIO_STREAM_STATE_STARTING);

    }

    return AAUDIO_OK;
@@ -280,9 +282,9 @@ aaudio_result_t AudioStreamTrack::requestPause() { 
              AAudio_convertStreamStateToText(getState()));

        return AAUDIO_ERROR_INVALID_STATE;

    }

    onStop();

    setState(AAUDIO_STREAM_STATE_PAUSING);

    mAudioTrack->pause();

    mCallbackEnabled.store(false);

    status_t err = mAudioTrack->getPosition(&mPositionWhenPausing);

    if (err != OK) {

        return AAudioConvert_androidToAAudioResult(err);
@@ -311,13 +313,13 @@ aaudio_result_t AudioStreamTrack::requestStop() { 
        ALOGE("requestStop() no AudioTrack");

        return AAUDIO_ERROR_INVALID_STATE;

    }

    onStop();

    setState(AAUDIO_STREAM_STATE_STOPPING);

    incrementFramesRead(getFramesWritten() - getFramesRead()); // TODO review

    mTimestampPosition.set(getFramesWritten());

    mFramesWritten.reset32();

    mTimestampPosition.reset32();

    mAudioTrack->stop();

    mCallbackEnabled.store(false);

    return checkForDisconnectRequest(false);;

}